Fig. 1. Schematic diagram of the experimental setup for the high-energy and high beam quality KTA-OPO

Fig. 2. Spatial intensity profile of pump beam，signal beam and idler beam

Fig. 3. The beam quality factors（M²）of the mid-infrared idler wave in tow orthogonal directions were measured

Fig. 4. Spectrum of the signal and idler outputs at the wavelength of 1.535 µm and 3.468 µm，respectively. Insets show the spectral bandwidth of the signal and idler outputs

Fig. 5. Signal and idler output energy as a function of the pump energy